This nonprovisional application incorporates by reference the subject matter of application Ser. Nos. 2000-238356 and 2000-238355 filed on Sep. 19, 2000, on which a priority claim is based under 35 U.S.C. xc2xa7119(a).
1. Field of the Invention
The present invention relates to a failure diagnosis apparatus and a failure diagnosis method for diagnosing failure of a vehicular electronic control system constituted by a plurality of electronic control related members mounted on a vehicle such as an automobile and a multiple communication line connected with the electronic control related members as communication elements.
2. Description of the Related Art
In recent years, in a vehicle such as an automobile, with improvements in basic functions and increases in high functions of the vehicle, the number of electronic control apparatus mounted on the vehicle are increased. As a result, the number of harnesses connected to the electronic control apparatus are considerably increased, increase in size and weight of harnesses are brought about, and thus attachment of harnesses and items surrounding the harnesses has become more difficult.
As a countermeasure, there has been developed a technology for carrying out multiple communication by connecting respective electronic control apparatus by a bus communication line (multiplex communication line) to thereby enable to resolve the above-described drawback. Further, since such a communication line is capable of sharing a large amount of information among the respective electronic control apparatus, more elaborate, control can be achieved.
For example, FIG. 9 is a schematic diagram showing such a vehicular electronic control system constituted by connecting a plurality of electronic control apparatus by a bus communication line. As shown by FIG. 9, there are provided a plurality of ECU (electronic control unit, controller) 101 through 104 as electronic control apparatus, all of the ECU 101 through 104 are connected to a bus communication line 110, and information can be transmitted and received among respective ECU 101 through ECU 104 by multiple communication by way of the bus communication line 110.
The ECU 101 through 104 are front ECU for controlling lamps, wipers and the like at a surrounding of a front portion of a vehicle body, sun roof ECU for controlling operation of a sun roof and so on. Therefore, the ECU 101 through 104 are connected to sensors or switches related to mechanism or control of control objects. In this case, first ECU 101 and second ECU 102 are respectively connected to switches 105 and 106, and third ECU 103 and fourth ECU 104 are respectively connected to motors 107 and 108.
According to such a vehicular electronic control system, when respective ECU (communication element) 101 through 104 are subjected to failure diagnosis, a diagnosis tester 120 is connected to a specific one of a communication element (here, second ECU) 102 and to ECU 102 as a gateway, and failure diagnosis information, transmitted from ECU 102 and ECU 101, 103, and 104 connected to ECU 102 by way of the bus communication line 110, is inputted to the diagnosis tester 120.
That is, when some drawback is caused in the electronic control apparatus related to ECU 101 through 104 constituting communication elements of the vehicular electronic control system, the diagnosis tester 120 is connected to ECU 102, self diagnosis information from the respective communication elements (ECU) 101 through 104 is inputted to the diagnosis tester 120 by way of ECU 102 as the gateway and based on the self diagnosis information, and it is diagnosed at which of the communication elements (ECU) failure is caused.
Further, when respective ECU is not provided with a self-diagnosis function, ECU 102 as the gateway is collectively provided with the self-diagnosis function.
Meanwhile, according to the above-described conventional failure diagnosis method of the vehicular electronic control system, the following problems are posed.
First, the diagnosis tester 120 is transmitted with the self diagnosis information by way of ECU 102 as the gateway and therefore, there is a case in which depending on diagnosis information, it is difficult to find at which of the communication elements (ECU), connected to ECU 102 as the gate way, the failure is present and whether the failure is present in ECU 102 as the gateway, and it is difficult to make clear cause of failure.
Further, although failure includes failure of the communication element (ECU) as well as failure of a signal transmitting system such as disconnection of a signal line or contact failure of a connection terminal, for example, when self diagnosis information is not transmitted, there is a case in which it is difficult to find whether the failure is in the communication element or in the signal transmitting system, and it is difficult to make clear the cause of failure.
Further, according to the conventional failure diagnosis method, the failure diagnosis is carried out based on the transmitted self-diagnosis information. Therefore, failure diagnosis cannot be carried out with regard to a communication element that is not provided with the self-diagnosis function. That is, the bus communication line 110 is connected not only to ECU having the self-diagnosis function, but also to a communication element that is not provided with the self-diagnosis function such as a switch or a sensor. The self-diagnosis information is not outputted from the communication element and therefore, the failure diagnosis cannot be carried out.
Further, when control is carried out based on a large amount of information provided by multiple communication, although finer control can be carried out, when failure is caused, combinations of cause of failure and phenomena of failure become complicated. Therefore, it is necessary to prepare trouble shooting with regard to a very large number of phenomena.
Therefore, not only an increase in a number of pages of an instruction manual of maintenance in cost for generating the instruction manual of maintenance are brought about, but also such a composite drawback per se becomes difficult to deal with.
Further, relationships between failure phenomena and failure causes are complicated and numerous. Therefore, an operator cannot memorize the relationships between failure phenomena and failure causes, and thus operational efficiency with regard to failure diagnosis is significantly deteriorated.
For example, using FIG. 9 as an example, when operation of the motor 107 has failed, the cause can be derived from failure of the motor 107 per se as well as failure of ECU 103, failure of ECU 101 route (including switch 105), failure of ECU 102 route (including switch 106), and failure of other communication system. Actually, relationships between failure phenomena and failure causes are extremely numerous. Further, there are a number of more complicated relations and operational burden is significantly applied to an operator conducting a failure diagnosis.
Therefore, the present invention has been conceived in view of the above-described problems, and it is an object thereof to provide a failure diagnosis apparatus and a failure diagnosis method of a vehicular electronic control system capable of diagnosing failure of a communication element (electronic control related member) which is not provided with self diagnosis function and failure of a signal transmitting system, and capable of analyzing a temporary drawback by instantaneous disconnection of a signal line or the like to thereby enable examination of failure cause more clearly.
In order to achieve the above-described object, according to one aspect of the present invention, a failure diagnosis apparatus for diagnosing a failure in a vehicular electronic control system, includes: a plurality of electronic control related members including electronic control apparatus mounted on a vehicle and controllers for electronically controlling the electronic control apparatus; a multiple communication system including a multiple communication line connected to the plurality of electronic control related members as communication elements; an input portion; and a signal analyzing portion, wherein communication signal information is received from the multiple communication line by way of the input portion connected to the multiple communication line, and the failure is diagnosed by analyzing the communication signal information at the signal analyzing portion. The signal analyzing portion is provided with a first and a second failed portion specifying means. In the first failed portion specifying means, a region which may have failed in the multiple communication system is specified from the communication signal information based on presence or absence of communication by the plurality of electronic control related members. In the second failed portion specifying means, the electronic control related member which may have failed in the plurality of electronic control related members is specified based on data content of the communication signal provided from the communication signal information.
Therefore, first, the multiple communication region which may have failed in the multiple communication system is specified from the communication signal information based on presence or absence of communication by the communication elements, the communication element which may have failed in the communication elements is specified based on the data content of the communication signal provided from the communication signal information. Therefore, by the diagnosis based on presence or absence of communication, there can be determined failure of a signal transmission system such as signal inputting and outputting systems of the multiple communication line and the respective communication elements connected thereto, and the failed communication element can be specified by diagnosis based on whether the data content of the communication signal is proper. Therefore, by utilizing the communication signal information, the failure diagnosis can be carried out efficiently and accurately and cause of failure can be predicted easily and more clearly.
Further, according to another aspect of the present invention, a failure diagnosis apparatus for diagnosing a failure in a vehicular electronic control system, includes: electronic control apparatus mounted on a vehicle; a plurality of electronic control related members including controllers for electronically controlling the electronic control apparatus; a multiple communication line connected to the controllers and the plurality of electronic control related members as communication elements; a recording portion, a detecting portion; and a display portion. The recording portion records states of the electronic control apparatus and proper value data of the plurality of electronic control related members with regard to the states of the electronic control apparatus in correspondence with each other. The detecting portion detects respective states of the plurality of electronic control related members based on communication signal information received from the multiple communication line. The display portion displays the proper value data recorded in the recording portion and detected data detected by the detecting portion and either of the proper value data recorded in the recording portion and the detected data detected by the detecting portion. Therefore, when there is a drawback in a certain electronic control apparatus, with regard to the controller for electronically controlling the electronic control apparatus as well as other electronic control related member for electronically controlling the electronic control apparatus, failure can easily be diagnosed by referring to the proper value data or the detected data displayed in the display portion.
Further, according to yet another aspect of the present invention, failure can be diagnosed more easily by specifying and displaying data of the detected data of the plurality of electronic control related members different from the proper value data recorded in the recording portion such that the data can be discriminated from other data.